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The control of humidity between certain limits is essential to avoid the alteration of historical objects, such as unstable historical glasses. However, the usual limits can be altered due to the presence of volatile organic compounds. This work presents the results of the exposure of soda, potash, and mixed‐alkali silicate glasses to neutral and acidic (formic) atmospheres with ∼30%, ∼70%, and ∼100% relative humidity. The hygroscopic capacity of the glass was analyzed by gravimetry, and the surface alteration was evaluated by infrared spectroscopy, optical microscopy, and ion chromatography. In all glasses, the alteration begins with alkali ions' lixiviation followed by the silica network's hydrolytic attack. The results showed that soda and mixed‐alkali silicate glasses exhibit similar behavior, while the potash‐lime one experienced the fastest degradation due to its composition. Results also confirmed that high humidity increased the alteration rate causing a higher hygroscopicity and reactivity of glasses. Finally, acidic environments promoted the ion‐exchange reaction at high humidity, accelerating the lixiviation of alkaline ions and promoting the diffusion of water into the glass network. [ABSTRACT FROM AUTHOR]

This paper reports the research on the physical-chemical response of silicate glasses subjected to the action of three natural soils types: acidic, neutral, and basic. The main goal of the study was to characterize the corrosion mechanisms acting upon glasses formulated with chemical compositions that are commonly found in historical glasses through an accelerated aging test that replicates natural burial. Resulting data showed a distinct and recognizable response of each glass type, with pH as the key variable for glass corrosion. Results can be of great significance to historical glass studies, especially in choosing suitable conservation strategies for archeological findings. [ABSTRACT FROM AUTHOR]